Air-cushion for steam-niggers



W. H. TROUT.

AIR CUSHIQN FOR STEAM NIGGERS. APPLICATION man MAY 31. 1911.

I Patented July 15, 1919.

. w raw/2:

mvvvalllllnvlvlr 5:454:51!

\ THE COLUMBIA PLANouRAPn co., wAsHlNdTON. D. c.

WILLIAM HENRY TROUT, OF MILWAUKEE, WISCONSIN, ASSIGNOR T0 ALLIS-CI-IALMERS MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE.

AIR-CUSHION FOR STEAM-N IGGERS.

Specification of Letters Patent.

Patented July 15, 1919.

Application filed May 31', 1917.- Serial No. 172,093.

To all whom it may concern:

Be it known that WVILLIAM HENRY TROUT, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, has invented a certain new and useful Improvement in Air- Cushions for Steam-Niggers, of which the following is a specification.

This invention relates to improvements in the construction of sawmill machinery and has particular relation to improvements in cushioning devices for reciprocating piston rods such as are ordinarily employed in steam niggers and the like. 7

An object of the invention is to provide a cushioning device for reciprocating piston rods, which is simple in construction and eflicient in operation. Another object is to provide a cushioning device especially applicable to the reciprocating piston rods of steam actuated niggers, which will effectively cushion the rod in its downward movement and which will permit discharge of water of condensation from the extreme lower extremity of the cylinder.

It has heretofore been customary in the construction of vertical nigger bar actuating cylinders to provide a cushion for the piston at the end of it's downward stroke, by automatically confining a smallamount of the steam ordinarily utilized as operating fluid, in the lower end of the cylinder. In some instances steam would condense and the waterof condensation would collect in the lower end of the cylinder. The piston in moving toward the lower head would strike the incompressible fluid or water of condensation and would damage the machine. In order to avoid such injury of the machine, the present invention contemplates providing means for'eflectively drainingthe water of condensation from the cylinder and for cushioning the piston rod without inter- I fering with such drainage.

A clear conception of an embodiment of the invention may be had by referring to the drawing accompanying and forming a part of this specification, in which like reference characters designate the same or similar parts in the various views.

Figure 1 is an elevation partly in section of a steam nigger showing its relation to a carriage.

Fig. 2 is a fragmentary central vertical section through one-of the actuating cylinders and the air. cushion thereof.

Flg. 3 1s an enlarged fragmentary sec" provided with an upper'head 9 penetrated by, and forming a guide for, the reciprocating piston rod 11 and having a cylindrical plunger formedintegral therewith. A

stufling box 13 prevents leakageof fluid from the interior of the cylinder past the rod 11. The cylindrical plunger 10 is adapted to enter the bore of a cushioning cap 8 associated with theupper extremity of the piston rod 11. The clearance between the periphery of the plunger 10 and the bore of the cap 8 is such that air confined in the interior of the cap by the plunger, must leak out gradually.

The pistons 12 are operable within the cylinder casings by means of actuating fluid such as steam'admitted through controlling valves 16 actuated by means of actuating stems 17 in the usual manner. The controlling valves 16 are of ordinary construction shown in detail in Fig. 3, 'andare adapted to alternately admit steam to, and release the same from, thechambers at opposite sides of the pistons 12. Theupper extremity of each of the cylinders 3,4 is pro vided with a steam connection15 somewhat below the upper head 9.- A connection 14-, usually provided with a check valve for preventing flow of fluid from the cylinder to the valve 16, permits admission of steam to the portion of the piston chamber above the connection 15; The lower connection 18.

enters the cylinder throughthe lower head.

As shown in Fig. 2 the plunger 10 is provided with a through port 19 and a flap 35 I its upward and'down'ward course of movevalve 20 which prevents air from passing through the port 19 when the plunger and cap approach each other but permits passage of air through this port as the cap 8 moves away from the plunger 10.

During the normal operation of the device the nigger bar 2 is moved upwardly and is oscillated sidewise by means of the pistons 12 to the faces of which steam under pressure is admitted through the valves 16. As the pistons 12 approach the upper extremities of their respective cylinders, small amounts of steam are confined in the portions of the cylinders above the connections 15, escape of this steam being prevented by the usual check valves in the connections 14. These upper cushions areof ordinary construction and are entirely satisfactory in operation.

As the pistons 12 approach the lower extremities of the cylinders, the caps 8 pass over the plungers 10 and confine small amounts of air, thus forming cushions for the pistons in their downward course of movement. As the bar 2 is gradually brought to rest, the air confined below the caps 8 escapes through the clearance be tween the cap bores and the peripheries of the plungers 10. As the caps 8 are moved away from the plungers 10, the flap valves 20 automatically open and permit air to enter the interior of the caps through the ports 19.- 1

It will' thus be noted that an effective cushioning of each of the pistons in both ment, is produced, while at the same time the location of the lower admission and discharge ports at the extreme lower end of each of the cylinders 3, 4 permits complete drainage of any water of condensation which may form in the cylinders. If it is found that chips or other undesirable mate- "rials accumulate at the upper ends of the" plungers 10, these plungers may be formed with downwardly inclined upper surfaces of such inclination that the material collecting thereon will slide off by gravity.

It should be understood that it is not desired tobe' limited to the exact details of construction herein shown and described, for obviousv modifications within 'thescope of the appended claims may occur to a person 7 skilled in the 7 Copies of this patent may he obtained for five cents each, by addressing the Commissioner of Patents,-

It is claimed and desired to secure by Letters Patent: 7

1. In combination, an upright cylinder having an upper head and having afluid discharge port at its lower extremity, a piston reciprocable in said cylinder and having a rod penetrating said cylinder head, a plunger associated with said cylinder head, and a cap associated with said piston rod and cooperable with said plunger to provide a cushion for said piston as it approaches said port.

In combination, an upright cylinder having a fluid discharge port at its-lower extremity, a piston reciprocable in said cylinder, a plunger associated with said cylinder, and a cap associated with said'piston rod and cooperable with said plunger to provide a cushion for said piston-as it ap proaches said port. I

3. In combination,v an upright cylinder element having a fluid discharge port at one extremity, a piston element within said cylinder element, said elements being, relatively reciprocable, a plunger associated with one of said elements, a cap associated with the other of said elements and cooperable with said plunger to provide a cushion as said port and piston element approach, and means for gradually arresting the motion of said elements in the opposite direction.

4. In combination, an upright cylinder having a fluid discharge port atits. lower iston element said elements bein rela-1 tively movable, a plunger associated with" one of said elements, a cap associated with the other of said elements and cooperable with said plunger to confineair andiprovide a closed cushioning chamber as said .elements approach each. other, and means for admitting air to said chamberto permit free relative receding of said elements.

y In testimony whereof, thesignature of theinventor is aflixed hereto; r i

7 WILLIAM HENRY TROUT.

Washington, D. G. 

